1. Field of the Invention
The invention relates to digital computer systems particularly with respect to work stations, personal computers (PC), terminals and the like.
2. Description of the Prior Art
Traditional mid to low end digital computer architecture comprises a monitor and a processor or CPU in a separate enclosure. Interface circuitry may also be included for interfacing the system to, for example, a LAN. The interface circuitry may also utilize a separate enclosure. The enclosures are interconnected by standard cabling and, traditionally, the monitor and processor each contains its own power supply. This architecture is commonly used in PCs, work stations, terminals and the like. The ubiquitous architecture described has numerous disadvantages. Such a multiple enclosure configuration tends to have an undesirably large foot print. For example, in a desk top system the CPU enclosure occupies a large amount of valuable office desk space. Additionally, such multiple enclosure configurations tend to be volumetrically wasteful with concomitant undesirable cost.
The prior art architecture requires large numbers of cables extending between the enclosures. This is undesirable not only because of the cost of such cabling, but also because of the electro-magnetic interference (EMI) certification that commercial equipment must undergo. The cabling and cable connectors are a source of noise which is difficult to eliminate. Expensive filtering is often required to reduce the EMI level to acceptable standards.
As described above, in conventional configurations the monitor and the processor each contains its own power supply. Such a power supply arrangement tends to be wasteful of space and cost because of duplication of components. This arrangement also engenders a disadvantage with respect to heat dissipation. Most of the heat, in such systems, is generated from the power supply. Monitors normally provide adequate heat dissipation by simple convection cooling. This is because the monitor enclosure is typically elevated on a pedestal so that appropriately placed cooling slots through the enclosure walls provide adequate free air convection current cooling. The power supply in the CPU enclosure, on the other hand, requires a cooling fan to dissipate the heat. This is because the processor enclosure normally is positioned flat on a desk top, thereby interfering with adequate free air convection cooling. Such cooling fans tend to add to the cost of the equipment and tend to be undesirably noisy. The cooling fan causes the distinctive hum associated with conventional PCs.
In addition to the above, a primary disadvantage of the described prior art architecture is that investments in equipment are traditionally lost when a system configuration is upgraded, or otherwise modified. For example, a PC upgrade involving obtaining new processor technology usually renders the entire CPU enclosure with its power supply obsolete.
It is appreciated from the foregoing, that the present day monitor does not perform any function unless one or more separate system components in separate enclosures are utilized therewith and connected thereto by standard cabling with all of the attendant disadvantages described above. For example, a standard VGA monitor connects to the parallel port of a CPU via a VGA cable connecting the VGA monitor port to the CPU parallel, port.
A prior art system may be considered as having a "personality" in accordance with the functionality that it is designed to perform. For example, a system can have the personality of a PC, a terminal or a work station. The system can have the 10-Mhz personality of a 286 processor, or the enhanced performance personality of a 20-Mhz 386 system. Generally, the personality of a system is fixed in accordance with the components assembled and interconnected to comprise the system. Changing the personality of the system generally entails replacing significant portions of the system with new components. Heretofore, there has not been any simple, easily implemented and economical way of changing the personality of an existing system.